Recently, the general trends in designing optical disc drives are toward small size, light weight and easy portability. In comparison with the half-height optical disc drive conventionally used in the desktop computers, the slim-type optical disc drive is widely used in notebook computers due to the reduced volume and its light weight.
Referring to FIG. 1, a typical slim-type optical disc drive 1 is shown. The slim-type optical disc drive 1 comprises a casing 10, a disc tray 12 and an optical pickup head 11 integrated into the disc tray 12. After an optical disc 16 is positioned in the disc tray 12, the disc tray 12 is pushed into the casing 10 for further reading operations. The slim-type optical disc drive 1 further comprises a signal transmitting apparatus 5 comprising a controlling circuit board 15, an operating circuit board 14 and a signal transmitting medium 13.
Typically, in the slim-type optical disc drive 1, a flexible printed circuit (FPC) 13 is used as a common signal transmitting medium 13 to make electrical connection between the operating circuit board 14 integrated within the disc tray 12 and the controlling circuit board 15 mounted within the casing 10. The flexible printed circuit 13 is easily bent and stretched in a narrow and crowded space. In addition, the properties of the flexible printed circuit 13 are low operating voltage, low power consumption, light weight and minimized electrostatic interference. Due to these special characteristics, the flexible printed circuit 13 is very widely used, for example, in the slim-type optical disc drives, digital cameras, printers, mobile phones, liquid crystal displays, MPEG Layer 3 (MP3) players, etc. However, the use of flexible printed circuit 13 is not cost effective because the flexible printed circuit 13 needs to be designed in a unique circuit. Therefore the cost of optical disc drive is increased.
For a purpose of reducing the manufacturing cost of the optical disc drive, a flexible flat cable (FFC) is used as the signal transmitting medium for the signal transmitting apparatus in the optical disc drive in replace of the conventional flexible printed circuit (FPC), as is described in, for example, US Patent Application No. 2004/0205785 A1.
Although the flexible flat cable (FFC) is cost effective, there are still some drawbacks. For example, electrostatic discharge (ESD) and electromagnetic interference (EMI) are readily generated in the flexible flat cable (FFC) during signal transmission. As known, ESD and EMI are detrimental to the electronic components of the optical disc drive.
Therefore the present invention is to provide a signal transmitting apparatus using a flexible flat cable (FFC) to overcome the drawbacks of the flexible flat cable (FFC) mentioned above.